1. Field of the Invention
This invention relates to a superplastic aluminum-based alloy material and a production process thereof.
2. Description of the Prior Art
Various metals or alloys, which exhibit an extraordinary elongation when being subjected to tensile deformation at high temperatures, are known as superplastic metals or alloys. Using the properties of such superplastic metals and alloys, parts having complicated shapes, which have not been easily produced by known processes, can be produced in a single production process and, thus, the superplastic materials are widely used in various industrial applications.
Known superplastic metals or alloys exhibit a large elongation at a strain rate of 10.sup.-4 to 10.sup.-2 s.sup.-1 (/second) and at a temperature T&gt;Tm/2 (i.e., at a temperature higher than their melting point.times.1/2 in terms of absolute temperature) and, thus, they are applicable for working at a relatively low strain rate. However, the known metals or alloys have difficulties in working at a relatively high strain rate exceeding 10.sup.-1 s.sup.-1.